Stretch-forging apparatus and method

ABSTRACT

A swing-forging die for stretch forming ductile materials is provided having an elongated die member, a pair of connecting rods extending transversely to the pass line and each pivotally connected at one end to opposite ends of said die member and mounted for rotation on spaced eccentrics mounted on shafts lying in a plane spaced from and parallel to said pass line, said eccentrics being arranged so that the eccentric at the entry end of the die rotates between 135* to 180* ahead of the eccentric connected to the delivery end of the die and in the same direction as the direction of movement of material on the pass line and a third eccentric mounted on a shaft in a plane parallel to the pass line and connected to one end of the die by a connecting rod whereby the die oscillates back and forth in a path parallel to the pass line simultaneously with the rotation of the spaced eccentrics.

United States Patent [72] Inventor Friedrich Kocks Dusseldorf, Germany [2]] Appl. No. 799,753 [22] Filed Feb. 17, 1969 [45] Patented June 8, [971 [73] Assignee Friedrich Kocks [54] STRETCH-FORGING APPARATUS AND METHOD 5 Claims, 1 Drawing Fig.

[52] US. Cl 72/189, 72/406 [51] Int. Cl B2ld 31/00 [50] Field of Search 72/189, 190, 214, 215, 216, 406, 450

[56] References Cited UNITED STATES PATENTS 1,549,527 8/1925 Fielding 72/l89 2,247,863 7/l94l Tiedenmann 72/189 Primary Examiner-Lowell A. Larson Att0rney-Buell, Blenko & Ziesenheim ABSTRACT: A swing-forging die for stretch forming ductile materials is provided having an elongated die member, a pair of connecting rods extending transversely to the pass line and each pivotally connected at one end to opposite ends of said die member and mounted for rotation on spaced eccentrics mounted on shafts lying in a plane spaced from and parallel to said pass line, said eccentrics being arranged so that the eccentric at the entry end of the die rotates between l35to 180 ahead of the eccentric connected to the delivery end of the die and in the same direction as the direction of movement of material on the pass line and a third eccentric mounted on a shaft in a plane parallel to the pass line and connected to one end of the die by a connecting rod whereby the die oscillates back and forth in a path parallel to the pass line simultaneously with the rotation of the spaced eccentrics.

PATENTEUJUN 8m 3.583192 mvsmon I Friedrich Kock I? S 1 STRETCH-FORGING APPARATUS AND METHOD This invention relates to stretch-forging apparatus and method and particularly to a device and method for stretch forging of ductile materials especially metallic materials by using at least one pair of swing-forging dies which move in opposite directions to each other and while approaching each other during the motion, they simultaneously move towards the exit side of the stretched material, thus deforming and feeding it. The forging dies are moved backwards at the same time they are separating from each other. Each one of these swing-forging dies is connected with two driven crank or eccentric drives by connecting rods mounted transverse to the feed direction and can be moved back and forth by an additional third connecting rod in the forging direction. This third additional connecting rod is mounted to a driven crank or eccentric drive on one end, which rotates at the same speed as the other drive parts, and controls with its other end the motion of the forging die.

It is possible to achieve unusually high cross section reductions in one pass on metallic materials through the swing-forging dies with devices of this kind for example on steel workpieces. Reductions of this amount cannot be made in one pass through a mill stand. The actual reductions obtained are l;l to 12:! and higher.

A problem in stretch forging is to obtain high efficiencies without an excessive load on the device, particularly its bearings. In an effort to arrive at a fairly high efficiency for the stretch-forging devices on one side, and on the other side to reduce the load on the device itself, especially on the bearings of the transverse connecting rod, 1 have found that the adjustment of the eccentric acting transverse to the feed direction upon the forging die is of very high importance. l have discovered through extensive investigation and practical experience that this goal can be reached when the transverse eccentric at the entry side of the swing-forging die is running ap proximately 180 or preferably l70l35 ahead of the transverse eccentric at the delivery side, and both eccentrics are turning in the same direction.

The result of such an eccentric adjustment is a very continuous material flow especially if the feed or parallel eccentrics are adjusted so that the feeding of the material is started as soon as the swing-forging dies touch the material stock.

ln the foregoing statement I have set out certain objects, purposes and advantages of my invention. Other objects, purposes and advantages of this invention will be apparent from a consideration of the following description and the accompanying drawing showing a swing forge die according to my invention.

Referring to the drawing, l have illustrated a swing-forge die according to my invention. lt is to be understood that in a swing forge die assembly two such dies would be used one on each opposite side of the piece being forged and connected so as to drive in unison. Swing-forging die 11 is connected with the eccentrics l and 16 by connecting rods 13 and 14 which are arranged transverse to the feed direction, indicated by arrow 12. The drive shafts 15A and 16A of eccentrics 15 and 16 are mounted parallel to the feeding direction. The direction of rotation of these eccentrics l5 and 16 indicated by arrows, is the same as the rotating direction of a pair of rolls working in the same direction. in relation to the direction of turning, the eccentric 15 at the entry side at the swing-forging die 11 shown at the left side of the drawing is operated approximately l50 ahead of eccentric 16 at the exit side of the swing-forging die. This lead as pointed out above means that eccentric 15 at the entry side is already approaching its bottom dead center position, and is, therefore, already deforming the workpiece before eccentric 16 leaves the indicated top dead center position and before the exit end of the swing-forging die approaches the workpiece.

Furthermore, it can be seen on the drawing that eccentric 18 which initiates the forward and return movement of swing forging die 11 and which is provided with the drive shaft 18A has already started the forward motion of swing-forgin die 11 through the connecting rod 7 before the eccentric 15 leaves the top dead center position.

As I have pointed out previously, an opposing swing-forging die mounted and operated in precisely the same way is mounted on the opposite side of workpiece 20. The eccentric l5 and its opposite counterpart are driven together as are eccentrics 16 and 18 are their counterparts so that the two swing dies operate in unison on opposite sides of the workpiece. While I have illustrated and described a presently preferred embodiment of my invention in the foregoing specification, it will be understood that this invention may be otherwise embodied within the scope of the following claims.

I claim:

1. A swing-forging apparatus for stretch forming ductile materials moving in a pass line comprising an elongated die member, a pair of connecting rods extending transversely to the pass line and each pivotally connected at one end to opposite ends of said die member and mounted for rotation on spaced eccentrics mounted on shafts lying in a plane spaced from and parallel to said pass line, said eccentrics being ar ranged so that the eccentric at the entry end of the die rotates between 135 to l ahead of the eccentric connected to the delivery end of the die and in the same direction as the direction of movement of material on the pass line and a third eccentric mounted on a shaft in a plane parallel to the pass line and connected to one end of the die by a connecting rod whereby the die oscillates back and forth in a path parallel to the pass line simultaneously with the rotation of the spaced eccentrics.

2. A swing-forging apparatus as claimed in claim 1 wherein the spaced eccentrics are arranged so that the eccentric at the entry end rotates 150 ahead of the eccentric at the delivery end.

3. A swing-forging apparatus as claimed in claim 1 wherein two die members are mounted identically on opposite sides of a workpiece and the corresponding drive shafts are connected for uniformly driving said shafts.

4. A method for stretch-forging ductile materials, comprising the steps of:

a. entering a workpiece between a pair of opposed elongated dies,

b. eccentrically moving the said die into and out of contact with the workpiece with the entry end of the die to 180 ahead of the exit end of the die,

0. simultaneously moving the die in the direction of the exit end thereof while the die is in contact with the workpiece,

d. moving the die in the direction of the entry end thereof while the die is out of contact with the workpiece, and

e. successively repeating the foregoing steps until the workpiece is carried through between said dies.

5. The method as claimed in claim 4 wherein the entry end of the die contacts the workpiece ahead of the exit end. 

1. A swing-forging apparatus for stretch forming ductile materials moving in a pass line comprising an elongated die member, a pair of connecting rods extending transversely to the pass line and each pivotally connected at one end to opposite ends of said die member and mounted for rotation on spaced eccentrics mounted on shafts lying in a plane spaced from and parallel to said pass line, said eccentrics being arranged so that the eccentric at the entry end of the die rotates between 135* to 180* ahead of the eccentric connected to the delivery end of the die and in the same direction as the direction of movement of material on the pass line and a third eccentric mounted on a shaft in a plane parallel to the pass line and connected to one end of the die by a connecting rod whereby the die oscillates back and forth in a path parallel to the pass line simultaneously with the rotation of the spaced eccentrics.
 2. A swing-forging apparatus as claimed in claim 1 wherein the spaced eccentrics are arranged so that the eccentric at the entry end rotates 150* ahead of the eccentric at the delivery end.
 3. A swing-forging apparatus as claimed in claim 1 wherein two die members are mounted identically on opposite sides of a workpiece and the corresponding drive shafts are connected for uniformly driving said shafts.
 4. A method for stretch-forging ductile materials, comprising the steps of: a. entering a workpiece between a pair of opposed elongated dies, b. eccentrically moving the said die into and out of contact with the workpiece with the entry end of the die 135* to 180* ahead of the exit end of the die, c. simultaneously moving the die in the direction of the exit end thereof while the die is in contact with the workpiece, d. moving the die in the direction of the entry end thereof while the die is out of contact with the workpiece, and e. successively repeating the foregoing steps until the workpiece is carried through between said dies.
 5. The method as claimed in claim 4 wherein the entry end of the die contacts the workpiece 150* ahead of the exit end. 